Generator relay shield



Jan. 11, 1944. A, HALLETT GENERATOR RELAY SHIELD Filed June 15, 1942 ALFRED 15611.457'7;

INVENTOR.

ATTORNEYS.

Patented Jan. 11, 1944 GENERATOR RELAY SHIELD Alfred Hallett, Los Angelcs, Calif., assignor to Hallett Manufacturing Company, Inglewood, Calif., a copartnership Application June 15', 1942, :SerialNo. 447,077

3 Claims.

This invention relates to the shielding and protection of electrical systems for internal combustion engines and other electrical systems operating in proximity to radio stations.

Electrical radiations from electrical systems including generators of internal combustion engines and generators used elsewhere in proximity to radio receiving apparatus are picked up in such apparatus and interfere with reception.

This is a serious factor in the operation of airplanes, motcrboats, submarines, military land vehicles, and all oth r types of transportation employing radio equipment as well as in stationary installations of generators in proximity to radio equipment.

Various forms of shielding have been employed for the purpose of grounding electrical radiations but I am not aware of any previous attempt to shield the relay of a generator.

Another problem arises in connection with the exposure of the elements of electrical systems to weather, oil and gas leakage and the like. Under heavy duty and adverse weather or operating conditions moisture, water, or oil and gas may be deposited on the relay and its terminals, etc., unless protected by moistureproof and water-proof enclosures. Inasmuch as a cable must lead to the generator system such protective means should include the regions where the cable enters the protective housing.

It is therefore an object of my invention to provide an electrical shielding for a generator relay which combines the function of physical protection to the elements of the relay unit against weather and other adverse operating conditions which contribute to failure of the system, deterioration of insulation, connections, etc.

It is a further and more specific object of my invention to provide a metallic shielding for a generator relay and associated elements which completely encloses and grounds the same, avoiding openings or cracks through which electrical radiations might escape, efiecting improved electrical connections at the terminals and physical protection of the system against the external conditions described.

It is a still further object of my invention to provide a generator relay shield of the character described which is adaptable to installation upon a conventional generator shell or housing and which is constructed in a manner to render readily accessible the relay and the connections thereto.

These and other objects of my invention will be made more apparent from a consideration of the full description and drawing This application is a continuation in part of my copending application Serial No. 427,621, filed January 21, 194-2, for Shielding for electrical systems.

In the drawing: I

Figure 1 is a vertical cross-sectional view of my generator relay shield installed upon the shell of a conventional generator.

Figure 2 is a top view partly insection of the same taken on the line 22 of Figure 1.

The :primary elements of the assembly illustrated are a generator Ill, a generator relay H, and a relay shield l2, the latter of which incorporates a low tension terminal l3 of novel design.

The generator is any conventional type, and the relay is also of any conventional design and construction performing the usual functions of a magneticswitch for controlling the generatorbatter-y circuit. The generator includes a shell or housing M of cylindrical form tapped and threaded at l5 for the reception of cap screws H5. The relay includes a curved base I1 concentric with the curve of the shell 14, and is formed with ears l8 provided with holes through which the cap screws I6 pass.

My novel shielding l2 comprises a base element 2-0 and a closure element 2|. The base 20 is formed with a curved seat 22 conforming to the contour of the shell M of the generator and adapted to be installed thereupon. The base and cover are of metal of substantially high conductive properties. The arrangement for assembling the base element'zll upon the generator in connection with the relay is particu larly illustrated in Figure 1, where the seat 22 rests upon the generator shell, the base portion I! of the relay is supported upon the seat 22, and the three parts are secured in the relationship shown and described by the cap screws 15. This arrangement enables the shield base to be securely attached to the generator but at the same time rendering the relay and the connections readily accessible from above. The closure element 2| is complementary to the base 20 and is provided with flanges 23 adapted to seat upon corresponding flanges 24 of the base 20 and to be detachably secured thereto by cap screws 25. Preferably the base 20 is relatively shallow and the closure relatively deep.

The metallic shield or housing l2 thus formed is sufliciently large to comfortably accommodate the relay H and its connections.

One of the relay connections 30 leads to the generator by a conductor 3| which may pass through the base 22 of the shield and the shell M of the generator. The other connection 32 of the relay may be carried to the battery (not illustrated) by a cable 33, and as this cable connection must extend through the shielding I use any suitable form of moisture-proof and waterproof terminal, a preferred form of which is shown in my aforesaid copending application Serial No. 427,621.

The cable 33 is covered by any suitable form of metal shielding 34 which may for example be woven wire or a tube. The terminal comprises a metal collar 3! formed with an annular shoulder 38 and screwed into the opening 39 in the base element. This collar has an internal annular ledge 40. Snugly fitting within the collar is an insulator 4| seating on the ledge 40, and being formed also witha beveled seat 42 at the upper end. Resting in this seat is a frusto conical insulating gland 43, preferably of soft rubber. A metal bushing 44 having a cylindrical portion through which the cable extends and a flat disc at the lower end is seated on the outer face of the gland 43. It is preferable that the cylindrical portion of the bushingbe inserted between the cable shielding 34 and the insulation 45 of the cable. The lower end of the cable shielding should be spread out over the disc portion of the bushing, and a ferrule 46 having a flange at its lower end rests upon the out-turned shielding and serves to center the cable. A threaded cap 4'! screws down on the collar 31 to secure the various parts tightly in place.

The terminal is locked securely to the housing, insuring an efficient and satisfactory connection with the relay and providing a moisture-proof and water-proof entry of the cable into the shield housing as well as a complete grounding of the metal cable shielding to the housing. I have tapped and threaded the base of the housing at the opposite side indicated by the numeral 50 for an optional location of the terminal, and closed the opening by a threaded plug By the foregoing I have achieved a generator relay unit completely enclosed in a structural sense as a protection against water, oil and dirt and completely shielded electrically by a housing which seats upon the generator shell and which has high conductive properties and which is positively connected with the cable shielding serving to dissipate into the ground all electrical radiations occurring in the unit.

Although I have herein shown and described my invention in what I have conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within thescope of my invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent structures.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. For use in combination with a generator having a cylindrical housing and a generator relay having a curved base concentric with the curve of said housing, a generator relay shield made of material having high conductive properties and comprising a moisture-proof and waterproof shield housing in separable parts, there being a base part having a seating portion concentric with the curve of said generator housing, the diameters of said generator housing, shield housing seating portion and relay base increasing in such order whereby they may be assembled by superimposing said shield housing seating portion on said generator housing and said relay base on said shield housing seating portion and retained in such relationship by bolts engagin said last named three elements, and the other part of said shield housing being a cover secured upon said base part by means independent of said bolts.

2. For use in combination with a generator having a cylindrical housing and a generator relay'having'a curved base concentric with the curve of said housing, a generator relay shield made of material having high conductive properties and comprising a moisture-proof and waterproof shield housing in separable parts, there being a relatively shallow base part having a seating portion concentric with the curve of said generator housing, the diameters of said generator housing, shield housing seating portion and relay base increasing in such order whereby they may be assembled by superimposing said shield housing seating portion on said generator housing and said relay base on said shield housing seating portion and retained in such relationship by bolts engaging said last named three elements, and the other part of said shield housing being a relatively deep cover secured upon said base part by means independent of said bolts.

3. For use in combination with a generator having a cylindrical housing and a generator relay having a curved base concentric with the curve of said housing, a generator relay shield made of material having high conductive properties and comprising a moisture-proof and waterproof shield housing in separable parts, there being a base part having a seating portion concentric with the curve of said generator housing, the diameters of said generator housing, shield housing seating portion and relay base increasing in such order whereby they may be assembled by superimposing said shield housing seating portion on said generator housing and said relay base on said shield housing seating portion and retained in such relationship by bolts engaging said last named three elements, and the other part of said shield housing being a cover secured upon said base part by means independent of said bolts, and a cable connection entering said shield housing through said base part and making an electrical connection between said base part and metal sheathing on said cable.

ALFRED HALLETT. 

